wifi: mac80211: handle ieee80211_radar_detected() for MLO

Currently DFS works under assumption there could be only one channel
context in the hardware. Hence, drivers just calls the function
ieee80211_radar_detected() passing the hardware structure. However, with
MLO, this obviously will not work since number of channel contexts will be
more than one and hence drivers would need to pass the channel information
as well on which the radar is detected.

Also, when radar is detected in one of the links, other link's CAC should
not be cancelled.

Hence, in order to support DFS with MLO, do the following changes -
  * Add channel context conf pointer as an argument to the function
    ieee80211_radar_detected(). During MLO, drivers would have to pass on
    which channel context conf radar is detected. Otherwise, drivers could
    just pass NULL.
  * ieee80211_radar_detected() will iterate over all channel contexts
    present and
  	* if channel context conf is passed, only mark that as radar
  	  detected
  	* if NULL is passed, then mark all channel contexts as radar
  	  detected
  	* Then as usual, schedule the radar detected work.
  * In the worker, go over all the contexts again and for all such context
    which is marked with radar detected, cancel the ongoing CAC by calling
    ieee80211_dfs_cac_cancel() and then notify cfg80211 via
    cfg80211_radar_event().
  * To cancel the CAC, pass the channel context as well where radar is
    detected to ieee80211_dfs_cac_cancel(). This ensures that CAC is
    canceled only on the links using the provided context, leaving other
    links unaffected.

This would also help in scenarios where there is split phy 5 GHz radio,
which is capable of DFS channels in both lower and upper band. In this
case, simultaneous radars can be detected.

Signed-off-by: Aditya Kumar Singh <quic_adisi@quicinc.com>
Link: https://patch.msgid.link/20240906064426.2101315-9-quic_adisi@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 41 insertions, 11 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 2e37d2639074..f94faa86ba8a 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -3467,11 +3467,16 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 	return ts;
 }
 
-void ieee80211_dfs_cac_cancel(struct ieee80211_local *local)
+/* Cancel CAC for the interfaces under the specified @local. If @ctx is
+ * also provided, only the interfaces using that ctx will be canceled.
+ */
+void ieee80211_dfs_cac_cancel(struct ieee80211_local *local,
+			      struct ieee80211_chanctx *ctx)
 {
 	struct ieee80211_sub_if_data *sdata;
 	struct cfg80211_chan_def chandef;
 	struct ieee80211_link_data *link;
+	struct ieee80211_chanctx_conf *chanctx_conf;
 	unsigned int link_id;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
@@ -3484,6 +3489,11 @@ void ieee80211_dfs_cac_cancel(struct ieee80211_local *local)
 			if (!link)
 				continue;
 
+			chanctx_conf = sdata_dereference(link->conf->chanctx_conf,
+							 sdata);
+			if (ctx && &ctx->conf != chanctx_conf)
+				continue;
+
 			wiphy_delayed_work_cancel(local->hw.wiphy,
 						  &link->dfs_cac_timer_work);
 
@@ -3504,9 +3514,8 @@ void ieee80211_dfs_radar_detected_work(struct wiphy *wiphy,
 {
 	struct ieee80211_local *local =
 		container_of(work, struct ieee80211_local, radar_detected_work);
-	struct cfg80211_chan_def chandef = local->hw.conf.chandef;
+	struct cfg80211_chan_def chandef;
 	struct ieee80211_chanctx *ctx;
-	int num_chanctx = 0;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
@@ -3514,25 +3523,46 @@ void ieee80211_dfs_radar_detected_work(struct wiphy *wiphy,
 		if (ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
 
-		num_chanctx++;
+		if (!ctx->radar_detected)
+			continue;
+
+		ctx->radar_detected = false;
+
 		chandef = ctx->conf.def;
+
+		ieee80211_dfs_cac_cancel(local, ctx);
+		cfg80211_radar_event(local->hw.wiphy, &chandef, GFP_KERNEL);
 	}
+}
 
-	ieee80211_dfs_cac_cancel(local);
+static void
+ieee80211_radar_mark_chan_ctx_iterator(struct ieee80211_hw *hw,
+				       struct ieee80211_chanctx_conf *chanctx_conf,
+				       void *data)
+{
+	struct ieee80211_chanctx *ctx =
+		container_of(chanctx_conf, struct ieee80211_chanctx,
+			     conf);
 
-	if (num_chanctx > 1)
-		/* XXX: multi-channel is not supported yet */
-		WARN_ON(1);
-	else
-		cfg80211_radar_event(local->hw.wiphy, &chandef, GFP_KERNEL);
+	if (ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER)
+		return;
+
+	if (data && data != chanctx_conf)
+		return;
+
+	ctx->radar_detected = true;
 }
 
-void ieee80211_radar_detected(struct ieee80211_hw *hw)
+void ieee80211_radar_detected(struct ieee80211_hw *hw,
+			      struct ieee80211_chanctx_conf *chanctx_conf)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
 
 	trace_api_radar_detected(local);
 
+	ieee80211_iter_chan_contexts_atomic(hw, ieee80211_radar_mark_chan_ctx_iterator,
+					    chanctx_conf);
+
 	wiphy_work_queue(hw->wiphy, &local->radar_detected_work);
 }
 EXPORT_SYMBOL(ieee80211_radar_detected);